/Engine/Plugins/Online/OnlineSubsystemUtils/Source/OnlineSubsystemUtils/Public/VoiceInterfaceImpl.h
Allows a remote talker to talk to the specified local player. NOTE: This only unmutes them in the game unless the bIsSystemWide flag is true, which attempts to unmute them globally
TRUE if the function succeeds, FALSE otherwise
virtual bool UnmuteRemoteTalker ( uint8 LocalUserNum, const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & PlayerId, bool bIsSystemWide )